A number of adjustable and lockable fixed bead bow sights are known in the prior art, and two examples of such sights are contained in U.S. Pat. Nos. 3,477,130 and 4,224,741. While these prior art adjustable bow sights are suitable for ground level hunting or shooting, they completely lack automatic range finding capability and therefore when employed for hunting from an elevated position require estimating of the range or guesswork by the hunter.
U.S. Pat. No. 4,120,096 discloses a bow sight which has range finding capability when used at an elevated position and also can be locked for usage in ground level shooting. However, the bow sight in this latter patent has several serious drawbacks, the most important of which is the inability of the bow sight to be adjusted for satisfactory use with various sizes of bows and various arrow shaft lengths and weights. This inability stems from the fact that the patented bow sight lacks any adjustment of the radial or automatic swing arc distance from the sight bead to the axis of rotation of the gravity activated pivoted mass carrying the sight bead or beads.
A major aim of the present invention is, therefore, to improve on an automatic range finding bow sight of the class shown in U.S. Pat. No. 4,120,096 through provision of a sight bead which is adjustably mounted on the pivoted mass in such a way that the effective radius and center of gravity of the mass relative to the axis of rotation of the pivoted mass may be infinitely varied, thus enabling the bow sight to be used on a wide range of bow sizes and with different arrow lengths and weights.
A further drawback of the bow sight in U.S. Pat. No. 4,120,096 which the present invention seeks to eliminate is the restricted range of rotational adjustability and locking of the rotational mass. In the present invention, the rotational mass carrying the independently adjustable sight bead can be adjusted through an infinite range circumferentially with respect to its rotational axis and can be locked in an infinite number of positions around said axis.
A further objective fully achieved by the invention is a substantial simplifying of the construction of the range finding bow sight compared to the construction of the bow sight in U.S. Pat. No. 4,120,096, thus rendering it more practical, more convenient to use, and comparatively less expensive to manufacture.
Other features and advantages of the invention will become apparent during the course of the following detailed description.